The Temporal Relationship Between Ovulation and an Injection of Progesterone or Corticosterone in the Hen Gallus domesticus

Corticosterone (1.5 mg) or progesterone (0.5 mg) was injected into hens within 2 h following the last oviposition of a sequence. The hens were killed 6.67, 7.00, 7.33, 7.67 and 8.00 h after injection. Ovulation was induced in 7.08 ± 0.01 h (ED5 0 ± s. e.) following an injection of corticosterone and in 7.41 ± 0.01 h ( ED5 0 ± s. e.) following an injection of progesterone.